The evidence of gene duplication for S-form NADP-linked isocitrate dehydrogenase in carp and goldfish

In the present paper, allelic polymorphism for electrophoretic variants of supernatant-form of NADP-linked isocitrate dehydrogenase (S-form IDH) was described in the surf smelt (Hypomesus pretiosus), the goldfish (Carassium auratus), and the carp (Cyprinus carpio). As in most other vertebrates including mammals, S-form IDH of the smelt was specified by a single gene locus. The goldfish and the carp, on the other hand, were endowed with two separate gene loci for S-form IDH. This apparent gene duplication was attributed to tetraploid origin of the goldfish and carp.This work was supported in part by a grant (CA 05138) from the National Cancer Institute, U.S. Public Health Service.Dr. Antonio Quiroz-Gutierrez is a postdoctorate fellow of the Institute for Biomedical Studies of the City of Hope Medical Center; he has also received support from the Ministry of Work, Mexico.     

Gene Duplication within the Family Salmonidae: Disomic Inheritance of Two Loci Reported to Be Tetrasomic in Rainbow Trout

We describe our studies of the genetics of allelic variation for NADP-dependent isocitrate dehydrogenase (IDH) in rainbow trout (Salmo gairdneri). Five populations of rainbow trout were studied to determine the phenotypic distribution of IDH; 453 progeny from a number of controlled matings were examined to determine the nature of inheritance of these alleles. The variation was found to be the result of four alleles producing protein subunits of differing electrophoretic mobilities. Progeny from crosses clearly demonstrated the presence of two disomic loci controlling the variation, rather than one tetrasomic locus as had been previously reported. These findings support our contention that the hypothesis of a tetraploid event in salmonid evolution should not be uncritically accepted.     

Isozyme analysis in a genetic collection of amaranths (Amaranthus L)

In various populations of the cultivated and weedy amaranth species, the electrophoretic patterns of alcohol dehydrogenase (ADH), glutamate dehydrogenase (GDH), malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH) and malic enzyme (Me) were studied. In total, 52 populations and two varieties (Cherginskii and Valentina) have been examined. Allozyme variation of this material was low. Irrespective of species affiliation, 26 populations and two varieties were monomorphic for five enzymes; a slight polymorphism of three, two, and one enzymes was revealed in three, nine, and fourteen populations, respectively. A single amaranth locus, Adh, with two alleles, Adh F and Adh S, controls amaranth ADH. Two alleles, common Gdh S and rare Gdh F, control GDH; no heterozygotes at this locus were found. The MDH pattern has two, the fast- and slow-migrating, zones of activity (I and II, respectively). Under the given electrophoresis conditions, the fast zone is diffuse, whereas slow zone is controlled by two nonallelic genes, monomorphic Mdh 1 and polymorphic Mdh 2 that includes three alleles: Mdh 2-F, Mdh 2-N, and Mdh 2-S. Low polymorphism of IDH and Me was also found, though their genetic control remains unknown.     

NADP+-isocitrate dehydrogenase in germinating and senescing pumpkin cotyledons

NADP⁺-isocitrate dehydrogenase (IDH, EC 1.1.1.42) was studied during the post-germinative growth of pumpkin ( Cucurbita pepo L. cv. Alberello di Sarzana) seedlings. In cotyledons. IDH activity increased in the dark and declined after illumination. Native PAGE showed that at least two isozymes of low electrophoretic mobility are present in cotyledons and absent in other pumpkin tissues. Anion exchange chromatography performed on extracts both from 4-day-old etiolated cotyledons and from illuminated cotyledons confirmed the trend of the IDH isoforms. In senescing cotyledons an additional IDH isoform with higher electrophoretic mobility appears. Overall the data indicate the presence of specific NADP⁺-IDH isoforms in etiolated cotyledons and senescing cotyledons, when glyoxylate cycle enzymes are active. A possible role for these IDH isoforms is proposed.     

Isozyme Analysis in a Genetic Collection of Amaranths (<Emphasis Type="Italic">Amaranthus</Emphasis> L.)

In various populations of the cultivated and weedy amaranth species, the electrophoretic patterns of alcohol dehydrogenase (ADH), glutamate dehydrogenase (GDH), malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH) and malic enzyme (Me) were studied. In total, 52 populations and two varieties (Cherginskii and Valentina) have been examined. Allozyme variation of this material was low. Irrespective of species affiliation, 26 populations and two varieties were monomorphic for five enzymes; a slight polymorphism of three, two, and one enzymes was revealed in three, nine, and fourteen populations, respectively. A single amaranth locus, Adh, with two alleles, Adh F and Adh S, controls amaranth ADH. Two alleles, common Gdh S and rare Gdh F, control GDH; no heterozygotes at this locus were found. The MDH pattern has two, the fast- and slow-migrating, zones of activity (I and II, respectively). Under the given electrophoresis conditions, the fast zone is diffuse, whereas slow zone is controlled by two nonallelic genes, monomorphic Mdh 1 and polymorphic Mdh 2 that includes three alleles: Mdh 2-F, Mdh 2-N, and Mdh 2-S. Low polymorphism of IDH and Me was also found, though their genetic control remains unknown.     

Genetic studies of murine catalase: Regulation of multiple molecular forms of kidney catalase

Starch gel electrophoresis of kidney catalase in inbred strains C3H and C57BL/6, their F₁ hybrid, and first and second backcross generations demonstrated that single-component (type A) v. multiple-component (type B) electrophoretic patterns are controlled by a single locus. The type A electrophoretic pattern is dominant. Twenty-five inbred strains of mice were classified according to their kidney catalase electrophoretic pattern. The data indicate that the segregating genetic factor determines a specific substance in the type A kidney which affects the electrophoretic mobility of catalase. A comparison of the F₁ hybrid enzyme with a 1:1 mixture of C3H and C57BL/6 enzyme showed that the alteration of electrophoretic mobility is the result of posttranslational modification of the catalase molecule. An association of kidney catalase electrophoretic pattern and the H-2 ^k haplotype indicates that the locus controlling the electrophoretic pattern is most likely located on chromosome 17 in close proximity to the H-2 complex.     

Esterase-16 (ES-16) of the rat (Rattus norvegicus): Identification and genetic characterization

Esterase-16, an esterase present in lung and other tissues of the laboratory rat, has been characterized by its biochemical properties (electrophoretic mobility, substrate pattern, sensitivity to inhibitors) and genetic variation in 107 inbred strains and substrains including 14 RI strains. It was classified as a carboxylesterase (EC 3.1.1.1). The phenotype ES-16A (BN/Han and 63 other strains) was defined as a narrow electrophoretic band migrating between ES-1A and ES-13A, ES-16B (LEW/Han and 42 other strains) exhibited the same electrophoretic mobility as ES-16A but was distinguished by its extremely weak activity. Segregation of ES-16 in RI strains and backcrosses indicated linkage to linkage group V (LGV). The Es-16 locus was tentatively placed into esterase cluster 2 and homology with Es-7 of the house mouse is proposed.     

The genetic basis of divergent pigment patterns in juvenile threespine sticklebacks

Animal pigment patterns are important for a range of functions, including camouflage and communication. Repeating pigment patterns, such as stripes, bars and spots have been of particular interest to developmental and theoretical biologists, but the genetic basis of natural variation in such patterns is largely unexplored. In this study, we identify a difference in a periodic pigment pattern among juvenile threespine sticklebacks (Gasterosteus aculeatus) from different environments. Freshwater sticklebacks exhibit prominent vertical bars that visually break up the body shape, but sticklebacks from marine populations do not. We hypothesize that these distinct pigment patterns are tuned to provide crypsis in different habitats. This phenotypic difference is widespread and appears in most of the freshwater populations that we sampled. We used quantitative trait locus (QTL) mapping in freshwater-marine F2 hybrids to elucidate the genetic architecture underlying divergence in this pigmentation pattern. We identified two QTL that were significantly associated with variation in barring. Interestingly, these QTL were associated with two distinct aspects of the pigment pattern: melanophore number and overall pigment level. We compared the QTL locations with positions of known pigment candidate genes in the stickleback genome. We also identified two major QTL for juvenile body size, providing new insights into the genetic basis of juvenile growth rates in natural populations. In summary, although there is a growing literature describing simple genetic bases for adaptive coloration differences, this study emphasizes that pigment patterns can also possess a more complex genetic architecture.     

The monotony of transferrin and esterase electrophoretic patterns in pirarucu, Arapaima gigas (Schinz, 1822) from Santa Cruz Lake, Tefé River, Amazonas, Brazil

Starch gel electrophoresis was used for examining the transferrin gene locus (Tf) and two esterase gene loci (Est-1 and Est-D1) of a pirarucu (Arapaima gigas) population sample collected from Santa Cruz Lake, Tefé River, Amazonas, Brazil. The Tf locus was tentatively classified as being polymorphic, showing two double-banded patterns (Tf(12) and Tf(22)) of the three theoretically expected ones (Tf(11), Tf(12) and Tf(22)), presumably controlled by two co-dominant alleles, Tf(1) and Tf(2). The monotony detected in pirarucu Tf locus genotypes showing a very high proportion of the double-banded heterozygote pattern Tf(12) (95% of the sampled individuals) may indicate the possibility of their having come from representatives of the same brood begotten by a pair of fish, where a single-banded Tf(11) homozygote pattern male would have crossed with a single-banded Tf(22) homozygote pattern female, or vice versa. One zone of electrophoretic activity was detected in esterase, presumably controlled by a monomorphic Est-1 locus with the fixed allele Est-1(1) where all individuals showed the single-banded Est-1(11) homozygote pattern. Esterase-D also displayed one zone of electrophoretic activity, presumably controlled by a monomorphic Est-D1 locus with a fixed allele Est-D1(1) where all individuals revealed the single-banded Est-D1(11) genotype pattern. The monotony comprised by single-banded genotype patterns in both esterase systems tested may also indicate the possibility of the individuals from the sample examined having come from representatives of the same brood begotten by a pair of fish with both the male and female having the same genotypes.     

Origin of the triosephosphate isomerase isozymes in humans: genetic evidence for the expression of a single structural locus.

A genetic approach is used to ascertain that a single structural locus for triosephosphate isomerase (TPI) (E.C.5.3.1.1.) is expressed in rapidly dividing human lymphoblasts. This approach is made possible through the identification of a rare electrophoretic variant of human TPI. The variant phenotype is expressed by the TPI-B isozyme in both erythrocytes and peripheral lymphocytes. The variant phenotype is also expressed in the thermostability and electrophoretic pattern of the TPI-A isozyme in mitogen-stimulated lymphoblasts, indicating that TPI-A and TPI-B are products of the same structural locus. These findings are in contrast to the recent conclusions of Yuan et al. based upon structural analysis, suggesting that the TPI-A and TPI-B isozymes are products of distinct structural loci.     

Genetic differentiation of freshwater and marine sticklebacks, (Gasterosteus aculeatus) of Eastern Europe

Electrophoretic variation of 13 presumptive enzymatic loci was studied in sticklebacks (Gasterosteus aculeatus) at 6 marine (Baltic) and 13 freshwater sites from Poland. Marine samples are significantly more variable (proportion of polymorphic loci, p # 0.38) than freshwater Samles (p # 0.12). Also the mean number of alleles per locus is significantly higher in the marine samples (n # 1.54) than in freshwater samples (n # 1.14). There is however no significant difference in values of mean heterozygosity between marine and freshwater sticklebacks. Some alleles are found in Baltic sticklebacks only, but all these occur in very low frequencies. Genetic distance between samples is low ranging from D = 0.000053 to 0.031410. However D is significant smaller between marine samples than between freshwater Samles. We suggest than this probaily is the result of larger genetic subdivision of freshwater populations. The low genetic divergence of marine and freshwater populations of the stickleback from poland might be expfained by the recent postglacial colonization of this area from a common refugium.     

The genetic architecture of parallel armor plate reduction in threespine sticklebacks

How many genetic changes control the evolution of new traits in natural populations? Are the same genetic changes seen in cases of parallel evolution? Despite long-standing interest in these questions, they have been difficult to address, particularly in vertebrates. We have analyzed the genetic basis of natural variation in three different aspects of the skeletal armor of threespine sticklebacks (Gasterosteus aculeatus): the pattern, number, and size of the bony lateral plates. A few chromosomal regions can account for variation in all three aspects of the lateral plates, with one major locus contributing to most of the variation in lateral plate pattern and number. Genetic mapping and allelic complementation experiments show that the same major locus is responsible for the parallel evolution of armor plate reduction in two widely separated populations. These results suggest that a small number of genetic changes can produce major skeletal alterations in natural populations and that the same major locus is used repeatedly when similar traits evolve in different locations.     

Lack of evidence for co-speciation in a parasitic nematode of grey kangaroos

Multilocus enzyme electrophoresis was used to compare specimens of the parasitic nematode Cloacina obtusa from the stomach of the eastern grey kangaroo, Macropus giganteus and the western grey kangaroo, M. fuliginosus. Allelic variation among nematodes was detected at 17 (85%) of 20 loci, but there was only a single fixed genetic difference (at the locus for isocitrate dehydrogenase, IDH) between C. obtusa from M. fuliginosus and those from M. giganteus in areas where each host occurred in allopatry. However, this fixed difference was not apparent within the zone of host sympatry. Although electrophoretic data indicate genetic divergence among allopatric populations of C. obtusa in the two host species, the magnitude of the electrophoretic difference (5%) between these populations does not refute the hypothesis that C. obtusa represents a single species. The 'usual' situation for parasitic helminths of grey kangaroos is that pairs of parasite species occur in the two host species. This situation differs for C. obtusa, where there has been a lack of speciation following a speciation event in its macropodid marsupial hosts. This finding suggests that a speciation event in the host does not necessarily lead to a speciation event for all its parasites and further highlights our lack of understanding of which processes drive speciation in parasites.     

Amylase polymorphism: studies of sera and duodenal aspirates in normal individuals and in cystic fibrosis.

Prior genetic studies of the human pancreatic amylase (Amy2) locus have been directed principally to the electrophoretic analysis of serum and urine, on the assumption that these fluids receive negligible contributions from the salivary (Amy 1) locus. In support of that assumption was the observation that the isozyme bands were lacking in patients with cystic fibrosis and in a postpancreatectomy patient. We have examined the sera of 97 patients having cystic fibrosis and find normal levels of serum amylase. On electrophoresis, three-quarters of the cystic fibrosis patients have a pattern (F-pattern) not observed in normal sera. The pattern is characterized by the absence of Pa 1. Comparative electrophoresis and mixing experiments indicate that the F-pattern is of salivary origin and is unmasked in cystic fibrosis by the absence of a pancreatic contribution. The normal serum pattern is considered to be an admixture of salivary and pancreatic amylase. On the assumption that duodenal fluids might more closely reflect the pancreatic (Amy 2) locus, electrophoretic studies were performed on 148 normal individuals and 37 individuals with cystic fibrosis. Electrophoretic phenotypes in duodenal aspirates are more complex than previously reported in studies of urine and serum; presumably because of the higher concentrations of amylase in the aspirates. Comparative electrophoresis and mixing experiments indicate that the phenotypes observed in duodenal aspirates also reflect admixture of pancreatic and salivary amylase. This recognition of pancreatic and salivary admixture in sera fortunately does not alter our prior understanding of the genetics of the Amy 2 polymorphism. The extensive studies which led to the delineation of the Amy 2 polymorphism were essentially based on the presence or absence of a variant band which proves now to be outside the zone of admixture.     

Molecular and developmental contributions to divergent pigment patterns in marine and freshwater sticklebacks

Pigment pattern variation across species or populations offers a tractable framework in which to investigate the evolution of development. Juvenile threespine sticklebacks (Gasterosteus aculeatus) from marine and freshwater environments exhibit divergent pigment patterns that are associated with ecological differences. Juvenile marine sticklebacks have a silvery appearance, whereas sticklebacks from freshwater environments exhibit a pattern of vertical bars. We investigated both the developmental and molecular basis of this population‐level variation in pigment pattern. Time course imaging during the transition from larval to juvenile stages revealed differences between marine and freshwater fish in spatial patterns of chromatophore differentiation as well as in pigment amount and dispersal. In freshwater fish, melanophores appear primarily within dark bars whereas iridophores appear within light bars. By contrast, in marine fish, these chromatophores are interspersed across the flank. In addition to spatially segregated chromatophore differentiation, pigment amount and dispersal within melanophores varies spatially across the flank of freshwater, but not marine fish. To gain insight into the molecular pathways that underlie the differences in pigment pattern development, we evaluated differential gene expression in the flanks of developing fish using high‐throughput cDNA sequencing (RNA‐seq) and quantitative PCR. We identified several genes that were differentially expressed across dark and light bars of freshwater fish, and between freshwater and marine fish. Together, these experiments begin to shed light on the process of pigment pattern evolution in sticklebacks.     

Biochemical polymorphisms in South African freshwater fish. Isoenzyme patterns in fish of the families Cyprinidae and Salmonidae

Isoenzyme patterns were studied in local populations of the carp ( Cyprinus carpio ) and the bream ( Sarotherodon mossambicus ) of the Cyprinid family. and in the trout ( Sabno giardneri ) of the family Salmonidae. Homogenates of heart muscle extracts were used in the identification of PGI. NADP-IDH. PGM and 6-PGD.
Polymorphisms found and gene frequencies obtained are discussed separately for each enzyme and species or population.
In the bream, variation was found only at the PGI locus. In the carp only the PGM locus was polymorphic whereas both PGM and IDH showed variation in the trout. The variation at the PGM locus in the trout cannot support the three locus model suggested elsewhere and clearly indicates a single locus for the mo-nomeric enzyme.
The large variety of NADP-IDH types in trout not only illucidates the complexity of this locus but confirms a disomic mode of inheritance. Genetic differences in the trout populations could be related to possible advantages for management purposes.     

Biochemical polymorphisms in South African freshwater fish. Isoenzyme patterns in fish of the families Cyprinidae and Salmonidae

Isoenzyme patterns were studied in local populations of the carp (Cyprinus carpio) and the bream (Sarotherodon mossambicus) of the Cyprinid family, and in the trout (Salmo giardneri) of the family Salmonidae. Homogenates of heart muscle extracts were used in the identification of PGI, NADP-IDH, PGM and 6-PGD. Polymorphisms found and gene frequencies obtained are discussed separately for each enzyme and species or population. In the bream, variation was found only at the PGI locus. In the carp only the PGM locus was polymorphic whereas both PGM and IDH showed variation in the trout. The variation at the PGM locus in the trout cannot support the three locus model suggested elsewhere and clearly indicates a single locus for the monomeric enzyme. The large variety of NADP-IDH types in trout not only illucidates the complexity of this locus but confirms a disomic mode of inheritance. Genetic differences in the trout populations could be related to possible advantages for management purposes.